CN108730051A

CN108730051A - The method and system sprayed for gaseous state and LPG

Info

Publication number: CN108730051A
Application number: CN201810347405.0A
Authority: CN
Inventors: J·N·阿勒瑞; R·D·珀西富尔
Original assignee: Ford Global Technologies LLC
Current assignee: Ford Global Technologies LLC
Priority date: 2017-04-18
Filing date: 2018-04-18
Publication date: 2018-11-02
Anticipated expiration: 2038-04-18
Also published as: US10393070B2; CN108730051B; DE102018109006A1; RU2018110668A; US20180298848A1

Abstract

This application involves the method and systems for gaseous state and LPG injection.Disclose the method and system to engine refuelling with liquefied petroleum gas (LPG).In one example, method includes directly injection rail being pumped into from (LPG) of fuel tank rather than intake port injection rail.Described can also include that LPG is supplied to intake port injection rail without making the LPG flow back into the fuel tank from the direct injection rail.

Description

The method and system sprayed for gaseous state and LPG

Technical field

This specification relates generally to the method and system of injection liquefied petroleum gas (LPG).

Background technology

The liquefied petroleum gas (LPG) being mainly made of propane can be used for internal combustion engine refuelling.It can be with various LPG is delivered to engine by phase (for example, liquid and gaseous state).In some instances, engine system can only include directly spraying Emitter；However, LPG inject directly on it is relatively hot under conditions of may be unsuitable because liquid LPG may be vaporized.? In other examples, engine system can only include passage injector；However, the intake port injection of LPG is in relatively cool item May be inappropriate under part, because gaseous state LPG may condense.In order to solve this problem, some engine systems can be The system that commonly known as port fuel directly sprays (PFDI) includes direct injection and intake port injection.In such PFDI In system, fuel is promoted from fuel tank by elevator pump, and fuel is then direct supplied into intake port injection fuel rail, Or the direct jet pump of elevated pressures is supplied fuel to, continue to be supplied to direct fuel injection rail later.

However, inventors herein have recognized that potential problems in relation to such PFDI systems when with LPG refuellings. As an example, liquefied petroleum gas (LPG) has about 96 DEG C of relatively low supercritical temperature.If directly spraying the temperature of rail Degree increase to the supercritical temperature of LPG or more, then directly injection rail in LPG may before it is injected into engine vapour Change, this may lead to the increase of air-fuel ratio error and combustion knock.

As another example, PFDI systems generally include the fuel return line for making excessive fuel back to fuel tank. For example, direct fuel injection rail coupling to fuel tank can be made fuel from direct fuel injection rail by fuel return line Flow back into fuel tank.However, such reflux pipeline increases the temperature of the LPG in fuel tank, and thus increase in fuel system LPG vaporization.If LPG steam reaches the entrance of direct jet pump, they may damage and/or reduce the volume effect of pump Rate.In this way, directly jet pump may need to pump cooling system and/or the enhancing of significant pressure, both of which increase fuel system The cost and complexity of system.

Invention content

In one example, the above problem can at least partly be solved by a kind of method, the method includes：It will Liquefied petroleum gas (LPG) from fuel rail is supplied to the injection of the direct injection in the cylinder for injecting fuel directly into engine Device；And make LPG flow to from the fuel rail be not direct injection injector charge-air fuel injector, without making the LPG Fuel tank is flowed back into, wherein the charge-air fuel injector injects fuel into the supply vapour from the position outside the cylinder In the air intake duct of cylinder.

In another expression, a kind of method for engine may include：LPG is pumped into direct injection from fuel tank (DI) fuel rail；Liquid LPG is directly injected to institute by the one or more directly injector by being connected to the DI fuel rails In at least one cylinder for stating engine；And the LPG of vaporization is sprayed onto from the DI fuel rails be not direct injector into Gas blowout emitter is without making the vaporization LPG flow back into the fuel tank.The method can also include deactivating direct jet pump Or elevated pressures pump.

In another expression, a kind of fuel system may include：Elevator pump；Direct fuel injection rail passes through the first combustion Material supply line is connected to the elevator pump；Intake port injection fuel rail in the downstream of the direct fuel injection rail and is led to The second fuel supply lines and the direct fuel injection rail coupled in series are crossed, wherein the intake port injection fuel rail and described Second fuel supply lines are in pressure more lower than the direct fuel injection rail；Injector is connected in the direct spray It penetrates between fuel rail and the intake port injection fuel rail so that the fuel from the direct fuel injection rail is supplied to institute State intake port injection fuel rail；And controller, it is electrically connected with the elevator pump and the injector, the controller includes The computer-readable instruction being stored in non-transient memorizer, described instruction are used for：It is carried to described with the direct jet mode of low pressure It rises pump and carries out feedback control；And feedback control is carried out to the injector to keep the pressure of the intake port injection fuel rail Power is less than the pressure of the direct fuel injection rail and is less than LPG liquid-gas pressure phase transitions, and the LPG liquid-gas pressure phase transition is based on The temperature of the intake port injection fuel rail.

By the way that LPG low pressure is directly injected in engine cylinder, can from fuel system removal/omission elevated pressures Direct jet pump, to reduce the cost and complexity of fuel system.It is retained in fuel system in direct jet pump but makes it In inactive example, the amount of pump intake can be entered by reduction fuel vapour to enhance the service life of pump.It can pass through In fuel system omit fuel return line and be originated from directly spray rail decompression (and therefore cooling down) steam It is cooling directly to spray rail to reduce fuel vapour.Omit cost and complexity that fuel return line further reduced fuel system Property.

In addition, by directly spraying rail with the LPG steam cooling of decompression, the vapour of the LPG in directly injection rail can be reduced Change, thus reduces air-fuel ratio error and combustion knock when directly spraying LPG.Accordingly, by using hotter direct spray Fuel rail is penetrated to heat the colder decompression LPG steam for including between direct fuel injection rail and intake port injection fuel rail, it can be with Thus the condensation for reducing the LPG in port fuel injection rail reduces air-fuel ratio error and increases engine performance and robustness. Therefore, steady LPG engines refuelling can be realized in the environment temperature and engine operating temperature of wider range.

It is briefly discussed above it should be understood that providing to introduce the simple shape of conceptual choice further described in a specific embodiment Formula.This is not meant to the key or substantive characteristics of the claimed theme of identification, the range of the claimed theme by Claims uniqueness after detailed description limits.In addition, theme claimed is not limited to solve the above or disclosure The embodiment for any disadvantage that middle any part is recorded.

Description of the drawings

Fig. 1 shows that according to an embodiment of the present disclosure includes the fuel system for being configured to injection liquefied petroleum gas (LPG) The schematic diagram of the example engine system of system.

Fig. 2 shows the example embodiments of the fuel system of Fig. 1 according to an embodiment of the present disclosure.

Fig. 3 shows utilization LPG according to an embodiment of the present disclosure to engine (engine system of such as Fig. 1) plus combustion The flow chart of the exemplary method of material.

Fig. 4 show it is according to an embodiment of the present disclosure for first by LPG be supplied to direct fuel injection rail and so LPG is supplied to the flow chart that port fuel sprays the exemplary method of rail from direct fuel injection rail afterwards.

Fig. 5 shows the figure of the exemplary liquid-gas transformation curve of LPG according to an embodiment of the present disclosure.

Specific implementation mode

The fuel system being related to for operating engine system (example engine system such as shown in FIG. 1) is described below System and method.Fuel system (example port fuel such as shown in Fig. 2 directly sprays (PFDI) fuel system) can be with Liquefied petroleum gas (LPG) is directly injected in engine cylinder (directly injection) by low pressure direct injector and/or is passed through LPG is ejected into the admission line of engine cylinder (intake port injection) by passage injector." admission line " is herein It can also be referred to as " air inlet port ".As described in the exemplary method in Fig. 3, can by the LPG of vaporization from directly spray (DI) fuel rail is supplied to intake port injection fuel rail.It can be by by the known liquid-gas phase of the pressure and temperature of LPG and LPG Varied curve (its example is shown in FIG. 5) is compared to determine the phase (liquid or gas) of LPG.Fig. 4 shows a kind of example Property method, wherein reach intake port injection fuel rail way in, the LPG in the LPG gas cooling DI fuel rails of vaporization.With this Mode, the LPG in DI fuel rails can keep liquid form for being directly injected in engine cylinder, and be supplied to The LPG of PFI rails can be remained in air inlet port of the gaseous form for intake port injection to engine cylinder.

About the term used in the entire specific implementation mode, high-pressure pump or direct injected fuel pump can be abbreviated as respectively HP pumps (alternatively, HPP) or DI petrolifts.Therefore, HPP and DI petrolifts may be used interchangeably directly is sprayed with referring to high pressure Petrolift.Similarly, low-lift pump can also be referred to as elevator pump.In addition, low-lift pump can be abbreviated as LP pumps or LPP.Air intake duct Fuel injection can be abbreviated as PFI, and DI can be abbreviated as by directly spraying.Moreover, fuel rail pressure or fuel rail are (more common Direct fuel injection rail) in fuel pressure force value can be abbreviated as FRP.Direct fuel injection rail can also be referred to as high compression ignition Expect rail, HP fuel rails can be abbreviated as.Moreover, the solenoid activation type entrance non-return for controlling the The fuel stream into HP pumps Valve can be referred to as overflow valve, solenoid activation type check-valves (SACV), electronically controlled solenoid activation type inlet non-return valve, And electronic control valve can also be referred to as.In addition, when solenoid activation type inlet non-return valve is activated, HP pumps be referred to as with Variable pressure pattern is operated.In addition, under variable pressure pattern, solenoid activation type check-valves can pump entire in HP Its state of activation is maintained in operating process.If solenoid activation type check-valves is deactivated and HP pumps rely on mechanical pressure tune Section is referred to as being grasped with mechanical mode or default pressure pattern without any order to electronic control spill valve, then HP pumps Make.In addition, under default pressure pattern, solenoid activation type check-valves can be maintained at it during the whole operation of HP pumps Dead status.

Fig. 1 depicts the combustion chamber of internal combustion engine 10 or the example of cylinder.Engine 10 can also be claimed herein For engine system 10.Engine 10 can be controlled by the control system including controller 12 at least partly, and by from The input control that vehicle operators 130 pass through input unit 132.In this example, input unit 132 include accelerator pedal and Pedal position sensor 134 is for the proportional pedal position signal PP of generation.Engine 10 cylinder 14 (herein also by Referred to as combustion chamber 14) may include the chamber wall 136 that piston 138 is positioned in.Piston 138 can be connected to bent axle 140 So that rotary motion of the convert reciprocating motion of piston at bent axle.Bent axle 140 can be joined by transmission system (not shown) It is connected at least one driving wheel of passenger carrying vehicle.In addition, starter motor (not shown) can be coupled by flywheel (not shown) To bent axle 140 to enable the start-up function of engine 10.

Cylinder 14 can receive air inlet by a series of air intake ducts 142,144 and 146 and 147.Air intake duct 142,144 and 146 can also be connected to other cylinders other than cylinder 14 of engine 10.However, air intake duct 147 includes admission line And it therefore can only be connected to, and can not connect with other cylinders of engine 10 with the cylinder 14 described in the example of Fig. 1 It is logical.In some instances, one or more air intake ducts may include increasing apparatus, such as turbocharger or mechanical supercharger. For example, Fig. 1 shows the engine 10 configured with turbocharger, the turbocharger include be arranged in air intake duct 142 with Compressor 174 between 144, and the exhaust steam turbine 176 along the arrangement of exhaust duct 158.

Air intake duct 146 may include the public inlet manifold that air is supplied to all cylinders of engine 10.Therefore, air inlet Road 146 can also be referred to as inlet manifold 146 herein.Therefore, engine intake duct may include single public air inlet Road, the single public air intake duct is in the part of the inlet duct including air intake duct 146.However, air intake duct 147 may include into Feed channel, and therefore can also be referred to as admission line 14 herein.Therefore, inlet manifold 146 is segmented into individually Admission line, then its respectively continue the different cylinders of supply engine 10.In the example of fig. 1, pass through separated inlet manifold 146 and the dotted line of admission line 147 depict the division between inlet manifold 146 and admission line 147.Therefore, air intake duct 147 May include an admission line, wherein air intake duct 147 can be Fig. 1 example in it is discribed supply cylinder 14 air inlet pipe Road.Therefore, engine 10 may include more than one admission line so that air is directed to engine from inlet manifold 146 Each cylinder.Therefore, all cylinders of 146 supply engine 10 of inlet manifold, and admission line 147 be only supplied it is discribed Cylinder 14.Engine 10 includes the independent admission line of each cylinder for engine 10, and is therefore wrapped in engine 10 The quantity of the admission line included can be equal to the quantity of the cylinder of engine 10.

Exhaust steam turbine 176 can give compressor 174 to provide power, wherein increasing apparatus at least partly by axis 180 It is configured as turbocharger.However, be provided in other examples of mechanical supercharger in such as engine 10, it can be optionally Exhaust steam turbine 176 is omitted, wherein the mechanical input from motor or engine can give compressor 174 to provide power.It can be with Inlet channel setting along engine includes the air throttle 162 of choke block 164, is provided to engine cylinder for change The flow velocity and/or pressure of air inlet.For example, as shown in Figure 1, air throttle 162 can be positioned at the downstream of compressor 174, or can replace Generation ground can be arranged in the upstream of compressor 174.

Other than cylinder 14, exhaust manifold 148 can also be received from other cylinders of engine 10 and is vented.Exhaust sensing Device 128 is shown coupled to the exhaust duct 158 of 178 upstream of emission control system.For example, sensor 128 can be from for providing It is selected in the various suitable sensors of the instruction of exhaust air-fuel ratio, such as linear oxygen sensors or UEGO (general or wide area row Gas oxygen) sensor, bifurcation lambda sensor or EGO (as depicted) sensor, HEGO (hot type EGO) sensor, NOx sensing Device, HC sensors or CO sensors.Emission control system 178 can be three-way type catalyst (TWC), NOx trap, it is various its His emission control system or combinations thereof.

Each cylinder of engine 10 may include one or more inlet valves and one or more exhaust valves.For example, vapour Cylinder 14 is shown as including at least one inlet poppet valves 150 at the upper area of cylinder 14 and at least one exhaust promotion Valve 156.In some instances, each cylinder (including cylinder 14) of engine 10 may include at the upper area of cylinder At least two inlet poppet valves and at least two exhaust poppet valves.

Inlet valve 150 can be controlled by controller 12 by actuator 152.Similarly, exhaust valve 156 can be by controlling Device 12 is controlled by actuator 154.During some conditions, controller 12, which can change, is supplied to actuator 152 and 154 Signal, to control the aperture (opening) and turndown ratio (closing) of corresponding inlet valve and exhaust valve.150 He of inlet valve The position of exhaust valve 156 can be determined by corresponding valve position sensor (not shown).Valve actuator can be motor-driven valve Activating profile or cam-actuated type, or combinations thereof.Can control inlet valve timing and exhaust valve timing simultaneously, or can use can Become admission cam timing, variable exhaust cam timing, double independent variable cam timings or any possibility for fixing cam timing. Each cam-actuated system may include one or more cams, and can utilize one of the following or multiple：Cam contour Line converts (CPS) system, variable cam timing (VCT) system, variable valve timing (VVT) system and/or lift range variable (VVL) system can be operated by controller 12 to change air door operation.For example, cylinder 14 can include alternatively logical Cross the inlet valve of motor-driven valve actuation control and the exhaust valve by the cam-actuated control including CPS and/or VCT.At other In example, inlet valve and exhaust valve can be by public valve actuator or actuating system or variable valve timing actuator or actuatings System controls.

In some instances, each cylinder of engine 10 may include the spark plug 192 for starting burning.It is selecting Under operation mode, ignition system 190 can in response to the spark advance signal SA from controller 12 and by spark plug 192 to Combustion chamber 14 provides pilot spark.However, in some embodiments, it is convenient to omit spark plug 192, such as engine 10 can be with (some diesel engines may be exactly such feelings in the case of starting burning by automatic ignition or by spraying fuel Condition).

In some instances, each cylinder of engine 10 may be configured to one for providing it fuel Or multiple fuel injectors.As non-limiting example, cylinder 14 is shown as including fuel injector 166,168 and 170.So And in other examples, engine 10 can only include fuel injector 166 and 168 and can not include fuel injector 170.In example further, engine 10 can only include fuel injector 166 and 170 and can not include fuel Injector 168.Fuel injector 166,168 and 170 may be configured to deliver the fuel received from fuel system 8.In Fig. 2 It is described in detail, fuel system 8 may include one or more fuel tanks, petrolift and fuel rail.Fuel system 8 may include One or more fuel, propane, butane, gasoline, diesel oil, bio-fuel etc..Fuel is more fully described below with reference to Fig. 2 The example of system 8 being more described in detail.

Fuel injector 166 is illustrated as being directly coupled to cylinder 14, for by electronic driver 167 from controller The pulse width of 12 received signal FPW-1 proportionally injects fuel directly into wherein.By this method, fuel injector 166 provide the direct injection (referred to below as " DI ") in so-called fuel to combustion cylinder 14.Therefore, fuel injector 166 It is referred to as DI fuel injectors 166 herein.When spraying liquefied petroleum gas (LPG), fuel injector 166 can be made It is operated for the direct injector of low pressure (LPDI).Therefore, LPG can be ejected into cylinder 14 by fuel injector 166, and cylinder pressure To be relatively low compared with cylinder pressure of power when such as injected petrol fuel.In the example of fig. 1, injector 166 is shown To be located in the over top of cylinder 14 and piston 138, between spark plug 192 and inlet valve 150.Due to some alcohol-based fuels Lower volatility, this position can by alcohol-based fuel operate engine when improve mixing and burning.However, another In one example, injector 166 can alternatively navigate to the side of cylinder 14.In another example, injector 166 is located at top Portion, closer to inlet valve to improve mixing.Fuel can be delivered from the fuel tank of fuel system 8 by petrolift and fuel rail To fuel injector 166.In addition, fuel tank can have the pressure transducer for providing signal to controller 12.In some examples In, the fuel supplied to DI fuel injectors 166 can only be pressurizeed by the elevator pump of fuel system 8 without passing through higher pressure Power direct jet pump pressurizes.However, in other examples, such as not supplying LPG to fuel injector 166 in fuel system 8 In the case of, the fuel supplied to injector 166 can be pressurizeed by both elevator pump and the direct jet pump of elevated pressures.

Intake port injection in providing air inlet port of the so-called fuel to 14 upstream of cylinder is (hereinafter referred to as " PFI ") configuration in, fuel injector 168 is illustrated as being arranged in admission line 147 rather than in cylinder 14.Therefore, it fires Material ejector 168 is referred to as PFI fuel injectors 168 herein.Fuel injector 168 can with pass through electric drive Device 169 proportionally sprays from fuel system 8 from the pulse width of 12 received signal FPW-2 of controller or from direct injector The fuel that 166 fuel rail receives.As being explained in more detail below with reference to Fig. 2, fuel injector 168 can be received and vaporized simultaneously Become gaseous LPG.Therefore, fuel injector 168 can spray gaseous state LPG.Note that two fuel injection systems are directed to, it can To use Single Electron driver 167 or 169, or multiple drivers can be used as depicted, for example, being used for fuel injection The electronic driver 167 of device 166 and electronic driver 169 for fuel injector 170.

As explained above, the air inlet from public inlet manifold 146 is transported to specific engines by admission line 147 Cylinder (cylinder 14 shown in the example of Fig. 1).Therefore, PFI fuel injectors 168 inject fuel into single admission line i.e. In admission line 147.By this method, the fuel sprayed by injector 168 can only be received there are one cylinder (cylinder 14).Separately Outside, engine 10 may include more than one PFI fuel injectors 168.Specifically, engine 10 can be in each air inlet pipe Road includes a PFI fuel injector 168 to provide fuel to each cylinder of engine 10.

Fuel injector 170 can be positioned in inlet manifold 146, and wherein engine intake duct includes to engine 10 All cylinder supply air flows single public passage.In such example, fuel injector 170 can be in commonly known as It is delivered fuel into public inlet manifold 146 in the system of centre fuel injection (CFI).Therefore, fuel injector 170 is herein In can also be referred to as CFI fuel injectors 170.Therefore, the fuel that fuel injector 170 is sprayed can be delivered to and is started Any one or more cylinders of machine 10.In some instances, it in inlet manifold 146 may include only one CFI fuel injections Device 170 is to deliver CFI.However, may include more than one CFI fuel injectors 170 in inlet manifold 146.At some May include CFI injectors or PFI injector in engine 10 in example.Therefore, although PFI injector and CFI injectors All show in the example of fig. 1, but it is to be understood that, engine 10 can only include one kind in two kinds of injector Injector.

Fuel injector 170 can be wide with the pulse by electronic driver 171 from 12 received signal FPW-3 of controller Degree proportionally sprays the fuel received from fuel system 8 or from the fuel rail of direct injector 166.Such as more below with reference to Fig. 2 It explains in detail, fuel injector 170, which can receive, has vaporized and become gaseous LPG.Therefore, fuel injector 170 can be with Spray gaseous state LPG.It should be noted that being directed to all fuel injection systems, Single Electron driver 167 or 169 can be used Or 171, or multiple drivers (such as in electronic driver 167,169 and 171 two or more) may be used to spray Penetrate fuel.For example, as described, electronic driver 167 can be used for fuel injector 166, and electronic driver 169 can be used for Fuel injector 168, and electronic driver 171 can be used for fuel injector 170.

In alternative exemplary, two or more in fuel injector 166,168 and 170, which can be configured as, to be used for Inject fuel directly into the direct fuel injector in cylinder 14.In another example, in fuel injector 166 and 170 Two or more can be configured as the port fuel injector in 150 injected upstream fuel of inlet valve.At other In example, cylinder 14 can only include single fuel injector, be configured to receive not from fuel system with different relative quantities With fuel as fuel mixture, and it is further configured to directly spray this fuel mixture as direct fuel injector This fuel mixture is ejected into inlet valve upstream into cylinder, or as port fuel injector.Therefore, it should manage Solution, fuel system as described herein should not be limited by the special fuel injector configuration described by way of example herein System.

Can during the single loop of cylinder 14 by one or more of injector 166,168 and 170 by fuel It is delivered to cylinder 14.For example, each injector can deliver a part for the total fuel injection burnt in cylinder 14.In addition, It is all as described below, from each injector deliver fuel distribution and/or relative quantity can with such as engine load, The operating mode of pinking and delivery temperature and change.It opening inlet valve event, closing inlet valve event (for example, substantially in air inlet Before stroke) during and during air inlet door operation the two of opening and closing, the fuel of intake port injection can be delivered. Similarly, for example, during induction stroke and partly previous during exhaust stroke, during induction stroke and portion Divide ground during compression stroke, the fuel directly sprayed can be delivered.Therefore, even for single combustion incident, the combustion of injection Material can be sprayed with different timings from passage injector and direct injector.In addition, for single combustive event, each follow Ring can execute the multi-injection of the fuel to being delivered.It can be in compression stroke, induction stroke or its any combination appropriate Period executes multi-injection.

In some instances, injector 166,168 and 170 can only spray the fuel of single type, such as LPG, (example Such as, liquid or gaseous LPG).However, in other examples, engine operating condition is depended on, injector 166,168 and 170 can be with Spray the fuel of different type or phase (for example, gaseous state and/or steam).For example, injector 166,168 and 170 can spray Replace back and forth between first fuel type (for example, gaseous state LPG) and the second fuel type (for example, liquid LPG) of injection.Such In example, injector 166,168 and 170 can only spray a type of fuel in each spraying cycle.However, at other In example, injector 166,168 and 170 can spray pluralities of fuel type in given spraying cycle.Injector 166 can be with For the fuel of given spraying cycle injection and 168 same type of injector 170 and/or injector.However, in other examples In, injector 166 can be directed to given spraying cycle injection and 168 different types of fuel of injector 170 and/or injector. For example, injector 166 can spray liquid LPG, and injector 168 and/or injector 170 can spray gaseous state LPG.

As described above, Fig. 1 illustrates only a cylinder of multicylinder engine.In this way, each cylinder can be similarly included Its own one group of inlet valve/exhaust valve, (multiple) fuel injector, spark plug etc..It should be appreciated that engine 10 may include Any appropriate number of cylinder, including 2,3,4,5,6,8,10,12 or more cylinders.In addition, each in these cylinders A may include some or all of the various parts for being described and being described by Fig. 1 with reference to cylinder 14.

Fuel injector 166,168 and 170 can have different characteristics.These include size difference, for example, an injection Device can have the spray-hole than another injector bigger.Other differences include but not limited to：Different spray angles, different operation Temperature, different target, different injection timings, different spray features, different location etc..In addition, depending on injector 170,168 and Different effects may be implemented in the distribution ratio of the fuel sprayed in 166.

Controller 12 is shown as microcomputer in Fig. 1 comprising microprocessor unit 106, input/output end port 108, the electronic storage medium for executable program and calibration value (is shown as in this particular example for storing executable instruction Non-transient ROM chip 110), random access storage device 112, not dead-file (KAM) 114 and data/address bus. Controller 12 can receive various signals from the sensor for being connected to engine 10, in addition to those previously discussed signals, Including：The measured value of induction Mass Air Flow (MAF) from mass air flow sensor 122；From being connected to cooling The engine coolant temperature (ECT) of the temperature sensor 116 of casing 118；It is sensed from the Hall effect for being connected to bent axle 140 The surface ignition pickoff signals (PIP) of device 120 (or other types)；Throttle position from throttle position sensor (TP)；And the absolute Manifold Pressure Signal (MAP) from sensor 124.Controller 12 can start according to signal PIP generations Machine rotating rate signal R PM.Manifold pressure signal MAP from manifold pressure sensor may be used to provide the vacuum in inlet manifold Or the instruction of pressure.

Fig. 2 is schematically depicted can be with the 8 same or similar exemplary fuel of fuel system that is described above with reference to Fig. 1 System 200.Therefore, fuel system 200 may include in the engine system (engine system such as described above with reference to Fig. 1 10) in.Fuel system 200 may be configured to directly spray liquefied petroleum gas (LPG) by direct injector and pass through Passage injector sprays LPG in gaseous form.It is to be understood, however, that fuel system 200 can additionally or can be replaced Generation ground injection is different from the fuel of LPG, the pinking inhibition stream of diesel oil, gasoline, ethyl alcohol, bio-fuel etc. and such as water Body.Elevated pressures pump (HPP) is not included in fuel system 200, or so that it is not worked when supplying LPG to engine, The low pressure for making it possible to achieve LPG is directly sprayed, and can reduce when running HPP LPG vaporizations due to the inlet HPP and The damage to HPP that may otherwise occur.Fuel system 200 can operate (the controller 222 by controller 222 Can be same or like with the controller 12 of Fig. 1) so as to execute below with reference to Fig. 3 and Fig. 4 example routine description some or All operations.

Fuel system 200 includes fuel tank 210, elevator pump 212, directly injection (DI) fuel rail 250, port fuel spray Penetrate (PFI) fuel rail 260 and engine cylinder body 202.Elevator pump 212 is referred to as lower pressure pump (LPP) herein 212.Therefore, fuel system 200 can be configured as port fuel and directly spray (PFDI) system comprising directly spray (DI) fuel rail 250 and port fuel spray (PFI) fuel rail 260.Fuel tank 210 and elevator pump are located in DI fuel rails 250 upstream.

Fuel tank 210 stores the fuel being loaded on vehicle.In some instances, fuel system 200 may include being more than One fuel tank is to keep different types of fuel.In one example, fuel tank 210 may include liquefied petroleum gas (LPG). LPG may include propane and/or butane.LPG can alternatively or additionally include other natural gases and it is liquefied can Fire the mixture of appropriate hydrocarbon gas.However, unshowned supplemental fuel tank may include addition type in fuel tank 210 and/or Fig. 2 Fuel, gasoline, diesel oil, alcohol etc..As another example, alcohol (for example, methanol, ethyl alcohol) can have the water being added to. As specific non-limiting example, fuel may include gasoline and ethyl alcohol (for example, E10 and/or E85).Fuel can be passed through Filling channel 204 provides fuel to fuel tank 210.Fuel tank 210 may include pressure sensor and/or temperature sensor with It is respectively used to estimation fuel tank pressure and/or fuel cell temperature.

LPP 212 can be at least partially disposed in fuel tank 210, and can be electric fuel pump.LPP 212 can To be operated from controller 222 (for example, controller 12 of Fig. 1) combustion is provided to one or more of fuel rail 250 and 260 Material.As an example, LPP 212 can be turbine (for example, centrifugation) pump for including electric (for example, DC) pump motor, therefore can To be increased by changing the pressure for being supplied to the electric power of pump motor to control pump both ends and/or by the volume flow rate of pump, thus Increase or decrease motor rotary speed.For example, since controller 222 can be sent to the power supply of elevator pump 212 and/or elevator pump 212 Signal, to reduce the electric power for being supplied to elevator pump 212.It is supplied to the electric power of elevator pump 212 by reducing, promotion can be reduced The volume flow rate and/or pressure for pumping both ends increase.On the contrary, the electric power of elevator pump 212 can be supplied to be carried to increase by increasing The volume flow rate and/or pressure for rising pump both ends increase.It as an example, can be from other energy on alternating current generator or vehicle Amount storage device (not shown), which obtains, is supplied to the electric power of lower pressure pump motor, thus control system can control for compared with The electric loading of low-pressure pump power supply.

Filter 217 can be arranged in the downstream of elevator pump 212, and can remove include in fuel can potential damage The small impurity of fuel treatment component.Fuel from fuel tank 210 is pumped into low pressure first passage 218 by elevator pump 212.So Afterwards, fuel can flow to DI fuel rails 250 from first passage 218.In some instances, HPP 214 may include in DI fuel The upstream of rail 250, between elevator pump 212 and DI fuel rails 250.

When being included in fuel system 200, HPP 214 can be engine-driven positive-displacement pump.It is non-as one Limitative examples, HPP 214 can be BOSCH HDP5 high-pressure pumps.HPP 214 can utilize solenoid activation type control valve (example Such as, fuel rate controller, magnetic spiral pipe valve etc.) 236 change effective pump volume of each pump stroke.The outlet non-return valve of HPP It is Mechanical course, and not electronically controlled by peripheral control unit.Compared with the LPP 212 of motor driving, HPP 214 can With by engine Mechanical Driven.HPP 214 includes pump piston 228, pump discharge chambe 205 (being also referred to as discharge chambe herein) and stepper chamber (step-room)227.Pump piston 228 receives mechanical input by cam 230 from engine crankshaft 140 or camshaft, thus root HPP is operated according to the principle of the simplex pump of actuated by cams.Therefore, cam 230 can pass through mechanical linkage 220 (such as axis, chain Item, belt etc.) it is mechanically coupled to bent axle 140 or camshaft.It is attached that sensor (being not shown in Fig. 2) can be positioned at cam 230 Closely, so as to determine the Angle Position (for example, between 0 degree and 360 degree) for the cam that may be forwarded to controller 222.

It is included in such example in fuel system 200 in HPP 214, fuel can be flowed by suction line 203 HPP 214, and HPP 214 can be left by outlet line 208.Therefore, when HPP 214 is included in fuel system 200 When, fuel can flow through HPP 214 in the way for reaching fuel rail 250.However, even if being included in fuel system in HPP 214 In example in 200, it can also draw around HPP when supplying LPG to fuel rail 250 including HPP bypass channels 226 Pilot material.Check-valves 274 and/or relief valve 272 can be between the outlet lines 208 and DI fuel rails 250 of HPP 214. Relief valve 272 can be parallel to check-valves 274 and be arranged in bypass channel 279, and can limit positioned at 214 downstreams HPP and Pressure in the DI supply lines 278 of 250 upstream of DI fuel rails.For example, relief valve 272 can will be in DI supply lines 278 Pressure is limited to upper threshold pressures (for example, 200 bars (bar)).Therefore, if control valve 236 (intentionally or unintentionally) is opened simultaneously And high pressure fuel pump 214 is pumping simultaneously, then relief valve 272, which can limit, incites somebody to action otherwise in DI supply lines 278 The pressure of generation.In some instances, HPP 214 may include leakage paths, and the leakage paths allow from bypass channel 279 The fuel small to the flow rate of bypass channel 211.

In addition, when HPP 214 is included in fuel system 200, fuel system 200 can optionally further include accumulator 215.When including accumulator 215, accumulator 215 can be located at downstream and the elevated pressures combustion of lower pressure petrolift 212 The upstream of material pump 214, and may be configured to keep the fuel of certain volume, reduce the combustion between petrolift 212 and 214 The rate that material pressure increases or decreases.For example, as shown, accumulator 215 can be connected in low pressure first passage 218, or Person is connected in the bypass channel 211 for the stepper chamber 227 that low pressure first passage 218 is connected to HPP 214.In other embodiment In, accumulator 215 can comply with fuel filter 217 and low pressure first passage 218 and be inherently present, and therefore may not be used Exist as discrete element.Alternatively, the approx. dimension that may be sized to pumpage of accumulator 215.Change speech It, upstream from room 227 or 205 be discharged fluid when, fluid may collect in accumulator 215, at the same minimize pipeline 218, Pressure change in 211 and/or 203.

In the example that HPP 214 is included in fuel system 200, HPP 214 can be deactivated permanently or it can be with It is temporarily deactivated.For example, when fuel system 200 only include the LPG as fuel and merely with LPG come when refilling, HPP 214 can permanently be deactivated so that it will never to be supplied to the LPG fuel of one or more of fuel rail 250 and 260 into Row pressurization.However, fuel system 200 replace between injection LPG and another fuel type of injection and/or utilization LPG and LPG in other examples for refilling, only can be supplied to 250 He of one or more fuel rails by another fuel type HPP 214 is deactivated when 260.Therefore, HPP operations (activation deactivates) can depend on the fuel supplied to fuel rail 250 and 260 Type.That is, when elevator pump 212 is different from fuel (such as Fuel Petroleum) of LPG to the supply of fuel rail 250, it can To activate HPP 214.Therefore, when supplying LPG to one or more of fuel rail 250 and 260, HPP 214 is deactivated.Work as quilt When activation, HPP 214 be supplied to the fuel of DI fuel rails 250 pressure increase to by LPP 212 pump fuel pressure with On；And when deactivated, HPP 214 not to received from elevator pump 212 and be supplied to one in fuel rail 250 and 260 or Multiple fuel adds pressure.

When HPP 214 is activated, controller 222 may be configured to by synchronously being encouraged with driving cam 230 or Control valve 236 (being configured based on solenoid valve) is deactivated to adjust the fuel flow rate for entering HPP 214 by control valve 236.It is living Plug 228 can pump.When piston 228 is advanced along the direction for reducing 205 volume of discharge chambe, HPP 214 is in compression Stroke.When piston 228 is advanced along the direction for increasing by 205 volume of discharge chambe, HPP 214 is in intake stroke.

Therefore, when HPP 214 is activated, solenoid activation type control valve 236 can be operable so that HPP 214 Increase fuel pressure.For example, valve 236 can be opened during the intake stroke of piston 228, and then in the pressure of piston 228 It is closed during contracting stroke so that piston 228 pressurizes to the fuel being introduced into during intake stroke in discharge chambe 205.With this side Formula can will be received from the fuel that elevator pump 212 is supplied in discharge chambe 205 during intake stroke by opening valve 236, And then during the compression stroke of piston 228, further pressurization can be carried out simultaneously to fuel by closing check-valves 236 Pump it to DI fuel rails 250.Controller 222 can be by adjusting the command signal and/or electric power supplied to control valve 236 It measures to adjust the position of control valve 236.For example, controller 222 and control valve 236 can be electrically coupled, and controller 222 can With by adjusting the command signal generated from controller pulse width and/or adjust the duty ratio of the electric power supplied to control valve To adjust the operation of control valve 236.

It includes that HPP 214 is made not work to deactivate HPP 214, so that it will not be pumped to by elevator pump 212 from case 210 The fuel addition pressure gone out.This can be for example by not providing power and thus by control valve to the control valve 236 of HPP 214 236 are maintained at open position to realize.Therefore, control valve 236 can be stayed open and can not be closed so that fuel can be with Valve 236 is flowed through during the intake stroke and compression stroke of piston 228 (in the upstream and downstream of valve 236).

In another example, deactivating HPP 214 can be realized by detaching HPP 214 with its power source.As one A example, in the case where HPP 214 is to provide the mechanically driven pump of power by bent axle 140, clutch or other release mechanisms 224 may include between HPP 214 and bent axle 140 to detach HPP 214 with bent axle 140.Controller 222 can with it is disconnected The actuator 225 of opening mechanism 224 is electrically connected to adjust the position of release mechanism 224, thus by HPP 214 and mechanical energy source (for example, bent axle 140) couples or separation.Therefore, controller 222 can adjust the actuator 225 for being sent to release mechanism 224 Electric signal (for example, pulse width) is adjusted to HPP 214 to will be switched off mechanism 224 and is connected to power source (for example, bent axle 140) engagement first position, or be adjusted to that HPP 214 detaches with power source are disengaged the second position.As an example, Actuator may include electromagnetic coil.

In another example, can HPP 214 and its power source manually for example be disconnected or be forbidden cam 230 Rotation deactivate HPP 214 manually.

It in another example, can simply omission/removal HPP 214 from fuel system 200, and therefore HPP 214 can not be included in fuel system 200.In such example from removal in fuel system 200/omission HPP 214, combustion The sole pump that material system 200 may include is LPP 212.In omission/removal HPP 214 from fuel system 200, individually connect Elevator pump 212 can be connected to DI fuel rails 250 by continuous fuel supply lines.Therefore, fuel can be by channel 218 from carrying It rises pump 212 and direct supplies to DI fuel rails 250, and without flowing through elevated pressures pump or other channels.In addition, elevator pump 212 will LPG is pumped directly into DI fuel rails 250, and will not be in the case where not making LPG flow into DI fuel rails 250 first by LPG It is pumped directly into PFI fuel rails 260.Therefore, when using LPG to engine refuelling, LPG must flow to PFI fuel rails DI fuel rails 250 are flowed through at least partly before 260.

Fuel can enter DI fuel rails 250 at the arrival end 241 of fuel rail 250.Fuel rail 250 may include being used for First fuel rail pressure sensor 248 of the instruction of the fuel pressure in fuel rail 250 is provided.Therefore, controller 222 can be with base Estimate and/or determine the fuel rail pressure of DI fuel rails 250 in the output received from the first fuel rail pressure sensor 248 (FRP).In addition, controller 222 can adjust the operation of elevator pump 212 based on the FRP determined according to pressure sensor 248. For example, controller 222 can adjust the arteries and veins of such as command signal by the FRP based on estimation and the difference between desired FRP Width is rushed to adjust the amount of power supplied to elevator pump 212.When supplying LPG to fuel rail 250, desired FRP or set point It is lower when can be than supplying another type of fuel (such as gasoline).That is, the case where needing to activate DI pumps 214 Under, when using LPG to engine refuelling, the desired pressure of DI fuel rails can give hair with Billy with another type of fuel It is lower when motivation refuelling.

Controller 222 can carry out the operation of elevator pump 212 feedback control to reach the expectation pressure of DI fuel rails 250 Power.When using LPG refuellings, DI pumps 214 do not work, and fuel is only therefore pumped into DI combustions by elevator pump 212 Expect rail 250.Elevator pump 212 can be merely able to LPG being pressurized to certain pressure.Therefore, elevator pump 212 can have it that can make The maximum pressure that the pressure rise of LPG is arrived.In this way, when using LPG refuellings, the desired pressure of DI fuel rails 250 can not More than the maximum pressure of elevator pump 212, the maximum pressure can be the outlet pressure of elevator pump 212.Therefore, with LPG to For DI fuel rails 250 for seasonable, the desired pressure of DI fuel rails 250 can be roughly the same or small with the outlet pressure of elevator pump 212 In the outlet pressure.

Fuel rail 250 can include additionally temperature sensor (such as temperature biography of the temperature for estimating fuel rail 250 Sensor 259).Therefore, controller 222 can be estimated to fire based on the output for the temperature sensor for including from fuel rail 250 Expect the temperature of rail 250.

DI fuel rails 250 dispense fuel into DI fuel injectors 252, at least portion of each DI fuel injectors 252 Ground is divided to be arranged in one in cylinder 264 for injecting fuel into cylinder 264.Controller 222 can be by directly spraying It penetrates driver 238 and individually activates each directly injector 252.Engine speed sensor 233 can be used for controller 222 The instruction of engine speed is provided.The instruction of engine speed can be used for identifying the speed of higher pressure fuel pump 214, this is Because engine 202 can for example pass through bent axle or camshaft mechanically transfer tube 214.

First PFI supply lines 246 can be connected to the outlet end 243 of DI fuel rails 250 in first end, and in phase To second end on be connected to the arrival end 245 of DI fuel rails cooling chamber 256.The outlet end 243 of DI fuel rails 250 can position Near the top of DI fuel rails 250 261 (ground relative to vehicle on the way), if the fuel in DI fuel rails 250 Then steam accumulates at this for vaporization.Therefore, PFI supply lines 246 can be connected to DI at a certain position of DI fuel rails 250 Fuel rail 250, if in DI fuel rails 250 there are gaseous state LPG if its accumulation at this location.

Therefore, DI fuel rails cooling chamber 256 may include the gaseous state LPG received from DI fuel rails 250, in than DI combustions Expect 250 lower pressure and temperature of rail.Cooling chamber 256 is thermally contacted with DI fuel rails 250 (reduces it to cool down DI fuel rails 250 Temperature).By this method, DI fuel rails 250 can transfer heat to the LPG in cooling chamber 256, thus heat cooling chamber 256 And enhance the vaporization of the LPG in cooling chamber 256.By this method, PFI fuel rails 260 only can supply gaseous state by DI fuel rails 250 LPG.However, in other examples, PFI rails can receive some liquid LPG from DI fuel rails 250.In addition, by using cooling The LPG of vaporization in room 256 cools down the LPG in DI rails, and cooling chamber 256 may insure that there is only liquid in DI fuel rails 250 State LPG.

In one example, cooling chamber 256 can be positioned at the outside of DI fuel rails 250, close to DI fuel rails 250 or with 250 co-planar contacts of DI fuel rails so that the heat from DI fuel rails can be for delivery to cooling chamber 256.Heat conducting element 257 can be with It is located between cooling chamber 256 and DI fuel rails 250 and physical connection cooling chamber 256 and DI fuel rails 250 to pass therebetween Pass heat.In the example of 250 contact coplanar with each other of cooling chamber 256 and DI fuel rails, as shown in the example of Fig. 2, heat conduction member Part 257 can be integrated in the wall of the contact coplanar with each other of cooling chamber 256 and DI fuel rails 250.In another example, cooling Room 256 may include in DI fuel rails 250.

Pressure regulator 254 may include in fuel system 200, so as to by cooling chamber 256 and PFI fuel rails 260 Pressure is maintained at than 250 lower pressure of DI fuel rail and gaseous state LPG is discharged from DI fuel rails 250.Therefore, pressure is adjusted Device 254 can be ensured by ejecting steam from DI fuel rails 250 when vaporization of liquid fuel in DI fuel rails 250 in DI Liquid LPG is only existed in fuel rail 250.Pressure regulator 254 may include entirely mechanical adjuster.In other examples, Pressure regulator 254 can by cooling chamber 256 injector and pressure sensor constitute.Additionally, pressure regulator 254 can The pressure of DI fuel rails 250 is maintained at desired injection pressure.In some instances, pressure regulator can passively be controlled The device of system.

However, in other examples, controller 222 can be with active control pressure regulator 254 to keep PFI fuel rails 260 pressure is less than the pressure of DI fuel rails 250, while DI fuel rails 250 are maintained at its desired pressure.Therefore, it controls Device 222 may be electrically coupled to pressure regulator 254, and can be by adjusting being sent to the command signal of pressure regulator 254 (for example, pulse width of command signal) adjusts the operation of pressure regulator 254.

In such example of active control pressure regulator 254, pressure regulator 254 may include injector.In this way, Pressure regulator 254 is referred to as injector 254 herein.Injector 254 can be towards the normally closed of closed position Type injector.In a closed position, no LPG flows through injector 254.Therefore, only it is expected will be from DI fuel rails 250 When LPG is supplied to PFI fuel rails 260, injector 254 can just be opened.If being supplied to the LPG of injector 254 not yet by vapour Changing, then LPG can be vaporized when being ejected into cooling chamber 256, this is because compared with the pressure of DI fuel rails 250, cooling chamber 256 In pressure reduce.Therefore, the LPG from DI fuel rails 250 can be ejected into cooling by controller 222 by injector 254 In room 256.Controller can for example be sent to the pulse width of the command signal of injector 254 to adjust injector 254 position.Controller can estimate DI fuel rails 250, cooling chamber 256 and PFI based on the temperature and pressure of corresponding component The phase of LPG in one or more of fuel rail 260.Specifically, controller can by the estimation temperature and pressure of LPG with The known liquid-gas transformation curve (being shown in FIG. 5 below its example) of LPG is compared.

In some instances, pressure regulator 254 may include at the outlet end of DI fuel rails 250 243.However at it In his example, pressure regulator 254 may include in PFI supply lines 246.In another example, pressure regulator 254 can To be included at the arrival end 245 of cooling chamber 256.Can with control pressure adjuster 254 so as to by 254 downstream of adjuster (for example, Cooling chamber 256, PFI fuel rails 260 etc.) pressure be maintained at the pressure Low threshold than 254 upstream of adjuster (DI fuel rails 250) Amount.For example, threshold quantity may include 10PSI.By this method, PFI fuel rails 260 may remain in lower than DI fuel rail 250 Pressure.However, controller 222 can coordinate the operation of elevator pump 212 and injector 254 so that can will come from DI fuel The LPG of rail 250 is supplied to PFI fuel rails 260, while keeping the desired pressure of DI fuel rails 250.

Gaseous state LPG can be directed to PFI fuel rails 260 from cooling chamber 256 by the 2nd PFI supply lines 266.PFI Supply line 266 can be connected to the outlet end 247 of cooling chamber 256 in first end, and couple in opposite second end To the arrival end 249 of PFI fuel rails 260.Therefore, by PFI supply lines 246 and 266 will from DI fuel rails 250 discharge and not Any LPG for being discharged into DI fuel injectors 252 is directed to PFI fuel rails 260.

PFI fuel rails 260 dispense fuel into passage injector 262 by intake port injection driver 237.Each into Gas-duct jetting device 262 can be positioned at the air inlet port of a cylinder 264 (for example, the above admission line described in Fig. 1 147) for injecting fuel into air inlet port in.Although each quilt in DI fuel rails 250 and PFI fuel rails 260 It is shown as distributing to fuel into four fuel injectors of respective injectors 252,262, it should be understood that each fuel rail 250 and 260 Fuel can be distributed to any appropriate number of fuel injector.As an example, DI fuel rails 250 can be by fuel point A fuel injector in first injector 252 of each cylinder of dispensing engine, and PFI fuel rails 260 can will fire Expect a fuel injector in the second injector 262 of each cylinder for distributing to engine.Controller 222, driver 237 May include control system with 238 and other suitable engine system controllers.Although driver 237,238 is illustrated as The outside of controller 222, it is to be understood that in other examples, controller 222 may include driver 237,238, Huo Zheke To be configured to provide the function of driver 237,238.Controller 222 may include unshowned additional component, such as including Component in the controller 12 of Fig. 1.

In another embodiment, instead of PFI fuel rails 260 and passage injector 262 or in addition to this, fuel system 200 may include center fuel injection (CFI) injector (for example, above CFI fuel injectors 170 described in Fig. 1), with Just inject fuel into public inlet manifold (for example, above describe in Fig. 1 inlet manifold 146) without be different into Feed channel.In such examples, the LPG from cooling chamber 256 can be directed to CFI sprays by the 2nd PFI supply lines 266 Emitter.Therefore, PFI supply lines 266 can be connected to the outlet end 247 of cooling chamber 256 in first end, and opposite It is connected to CFI injectors in second end, rather than PFI fuel rails 260.Therefore, can will from DI fuel rails 250 discharge and not Any LPG for being discharged into DI fuel injectors 252 is directed to CFI injectors.

In other example, CFI fuel injectors and PFI fuel rails 260 including passage injector 262 can It is included in fuel system 200.In such example, PFI supply lines 266 can separate the fuel from DI fuel rails 250 And it is delivered to each in CFI injectors and PFI fuel rails 260 respectively.

CFI injectors can be connected to inlet manifold at the position of admission line upstream.That is, being divided into manifold Before different admission lines, CFI injectors can be connected to inlet duct at the position of public inlet manifold upstream.Cause This, CFI injectors can inject fuel at a certain position of inlet duct in engine intake duct, at this location It has sprayed fuel and then can be supplied in any one admission line and associated engine cylinder.

PFI fuel rails 260 can include additionally pressure sensor 258 and temperature sensor 259.Controller 222 can be with Estimate the pressure of PFI fuel rails 260 based on the output received from pressure sensor 258, and is based on from temperature sensor 259 What is received exports to estimate the temperature of PFI fuel rails 260.Therefore, pressure sensor 258 and temperature sensor 259 can electricity It is coupled to controller 222.

Controller 222 can adjust the behaviour of injector 254 based on the pressure of the estimation of PFI fuel rails 260 and/or temperature Make.For example, controller can adjust the operation of injector 254 so that PFI fuel rails 260 are maintained at desired pressure.For example, Controller 222 can adjust spray based on the difference between the expectation FRP of the estimation FRP and PFI fuel rails of PFI fuel rails 260 The operation of emitter 254, for example, command signal pulse width.Therefore, when the PFI fuel rail pressures of measurement are more than desired value, Controller 222 can reduce the amount of the LPG sprayed by injector 254 and therefore reduce the LPG for being supplied to PFI fuel rails 260 Amount；And when PFI fuel rail pressures are less than desired value, controller 222 can increase the LPG's sprayed by injector 254 It measures to increase the amount for the LPG for being supplied to PFI fuel rails 260.Desired FRP or set point can depend on admission line pressure Power, wherein for higher admission line pressure, desired FRP can be with higher.

In one embodiment, it in the case where HPP 214 is included in fuel system 200, can optionally include low Press second channel 288 so that fuel is directly directed to PFI fuel rails 260 from elevator pump 212, without flowing a fuel through DI fuel Rail 250.For example, when the LPG of 214 upstreams HPP is gaseous state or close vaporization, controller 222 can be opened positioned at second channel Valve 289 in 288 by LPG to be conducted directly to PFI fuel rails 260.In addition, when only it is expected intake port injection, controller 222 can close valve 236 only to allow fuel to flow to PFI fuel rails 260 while keeping valve 289 to open.Show another In example, when giving engine refuelling using the fuel (such as gasoline) different from LPG, controller 222 can open valve 289. Therefore, may include second in the gasoline, diesel oil or another fuel that confession is directly sprayed in requisition for activation HPP 214 Channel 288 is not for by the intake port injection of the fuel to pressurize of HPP 214.

Therefore, fuel system 200 does not include the fuel return line from any of fuel rail 250 or 260.Cause This, once fuel pumps out fuel tank 210 by elevator pump 212, fuel would not flow back into fuel tank 210, unless it is from fuel Certain point of both fuel rails 250 and 260 in system 200 upstream flows back into fuel tank 210.Therefore, once fuel reaches fuel As soon as in rail 250 and 260 injects fuel directly into engine cylinder by directly spraying (DI) fuel injector 252 In 264, or (PFI) fuel injector 262 is sprayed by port fuel and injects fuel into one or more air inlet ports In.In another example, engine can include alternatively or additionally that one or more center fuels spray (CFI) injection Device is for injecting fuel into inlet manifold or air intake duct.Fuel can direct supply to CFI injectors from fuel rail 250 Without flowing back into fuel tank 210.Therefore, engine cylinder 264 can be supplied fuel to by one or more of mode： It is injected fuel directly into one or more engine cylinders 264 by DI fuel injectors 252, passes through PFI injector 252 Fuel air road is ejected into the air inlet port of engine cylinder 264, and by one or more CFI injectors by fuel It is ejected into inlet manifold or the air intake duct of engine.

In addition, when supplying LPG to fuel rail 250 and 260, DI fuel rails 250 and PFI fuel rails 260 are in fuel system It is coupled to one another in series in 200 so that fuel has to flow through another before a fuel rail in flowing to fuel rail 250 or 260 A fuel rail.In the figure 2 example, DI fuel rails 250 are located at the upstream of PFI fuel rails 260 so that the combustion pumped from case 210 Material flows first to DI fuel rails 250.

In some cases, at least part for being pumped into the fuel of DI fuel rails 250 then can be from DI fuel rails 250 Direct supply to PFI fuel rails 260.For example, when liquid LPG vaporization so that there are when gaseous state LPG in DI fuel rails 250, At least part of gaseous state LPG can be supplied to PFI fuel rails 260.In other examples, due to PFI fuel rails compared with Low-pressure, liquid LPG may be vaporized when being ejected into PFI fuel rails from DI fuel rails.It is to be understood, however, that at other During engine operating condition, fuel can not flow to PFI fuel rails 260 from DI fuel rails 250.In such example, pass through promotion All fuel that pump 212 is supplied to DI fuel rails 250 may remain in DI fuel rails 250, and/or can be reached in fuel It can be ejected into engine cylinder 264 before PFI fuel rails 260.

When fuel flows to PFI fuel rails 260 from DI fuel rails 250, fuel does not flow back into fuel tank 210, but directly PFI fuel rails 260 are flowed to from DI fuel rails 250.Therefore, any fuel of outflow DI fuel rails 250 all flows directly to PFI fuel Rail 260, and any part positioned at 250 upstream of DI fuel rails of fuel system 200 (including fuel tank 210) is not flowed back into. In this way, only supplying fuel from DI fuel rails 250 to PFI fuel rails 260.By this method, the The fuel stream in fuel system 200 is single To, i.e., from fuel tank 210 to DI fuel rails 250, and PFI fuel rails 260 are then continued in some instances.Therefore, The heating of fuel tank 210 can be reduced, and the pipeline in fuel system 200 can be reduced by eliminating fuel return line Connection amount (amount of plumbing).

Controller 222 can control the operation of each injector 252 and 262.For example, controller 222 can be controlled from every The distribution of the fuel of a injector delivering and/or relative quantity, can be with operating mode (such as engine loading, pinking and exhaust Temperature) and change.Specifically, controller 222 can be by port fuel jet drive 237 and direct jet drive 238 transmission proper signals adjust direct fuel injection ratio, this can with desired pulse width further actuating accordingly into Port fuel injector 262 and direct injector 252 are for the desired injection ratio of realization.Additionally, controller 222 can be with base (that is, activate or deactivate) 252 He of one or more injectors is selectively enabled and disabled in the fuel pressure in each rail 262.The example control scheme of controller 222 is shown below with reference to Fig. 3.

Fig. 3 and Fig. 4 are gone to, they show for operating the fuel system that can spray LPG (for example, above in fig. 2 The fuel system 200 of description) exemplary method flow chart.Controller (such as above controller 12 described in Fig. 1 and/ Or more the controller 222 that describes in fig. 2) may include be stored in non-transient memorizer for executing in Fig. 3 and Fig. 4 The instruction of the method for description.Specifically, controller can adjust one of the following or multiple operations：Elevator pump (for example, with On the elevator pump 212 that describes in fig. 2), LPG steam jet ejectors (for example, above injector 254 described in fig. 2), DI pumps Inlet valve (for example, control valve 236 of the above HPP 214 described in fig. 2) and one or more fuel injector (examples Such as, the above injector 252 described in fig. 2 and 262 and above fuel injector 166,168 and described in Fig. 1 170), so that utilization LPG gives engine (for example, above engine 10 described in Fig. 1) refuelling.

Fig. 3 is paid close attention to, it illustrates for directly spraying and/or the exemplary method of intake port injection LPG 300.Higher (vaporization of wherein LPG is advantageous and/or is more likely), method at fuel rail temperature and lower fuel rail pressure 300 may include gaseous state LPG being ejected into admission line by one or more PFI injectors, and/or pass through one or more Gaseous state LPG is ejected into inlet manifold by a CFI injectors.Under colder engine temperature or environment temperature (wherein LPG's Condensation is advantageous and/or is more likely), method 300 may include directly will by one or more directly injectors LPG low pressure is directly injected in engine cylinder.Therefore, when, there are when gaseous state LPG, this method may include air intake duct in DI rails Injection and/or center fuel spray LPG.When gaseous state LPG is not present in DI rails, this method can include additionally directly spraying It penetrates.In addition, this method may include removing gaseous state LPG in PFI rails by the way that gaseous state LPG to be ejected into, and waiting for the start is straight Injection is connect, until removing essentially all of gaseous state LPG from DI rails.Controller can by by the temperature of fuel rail and The liquid-gas transformation curve (being shown in FIG. 5 below its example) of pressure and LPG are compared to the LPG's in estimation fuel rail Phase (gaseous state or liquid).

In some instances, method 300 may include that low pressure directly sprays both LPG and intake port injection LPG.At other In example, method 300 may include that low pressure directly sprays both LPG and center fuel injection LPG.In other example, side Method 300 may include the whole of direct injection LPG, intake port injection LPG and center fuel injection LPG.In addition, the side in Fig. 4 Method 400 may include coming from cooling DI rails by the way that the part for the LPG for including is discharged in DI rails, subtract to the LPG being discharged Pressure and therefore cooling LPG be discharged, and then DI rails are cooled down with the LPG of colder, less pressurization.Added with colder, less The LPG of pressure can heat the LPG of colder, the less pressurization to cool down DI rails also, and PFI injector or CFI are supplied to increase The vaporization of the LPG of injector.

Method 300 starts at 302 comprising estimation and/or measurement engine operating condition.Engine operating condition may include with It is one or more of lower：Fuel cell temperature, fuel tank pressure, fuel rail temperature, fuel rail pressure, operator demand's torque, Engine speed etc..

Then method 300 proceeds to 304 from 302 comprising determine for the fuel to engine refuelling whether be liquid Liquefied oil gas (LPG).In some instances, LPG can be unique onboard fuel, in this case, fuel be LPG and Method 300 from 304 proceeds to 308.Therefore, it is configured as in the only example of LPG fuel system in fuel system, method 300 can Not include step 304, and method 300 can directly proceed to 308 from 302.However, utilizing more than one combustion in engine In other examples for expecting type, method 300 can include determining whether it is expected LPG refuellings at 304.For example, when one or When LPG present in multiple onboard fuel casees (for example, above fuel tank 210 described in fig. 2) is more than other fuel types, It can be desirable to LPG refuellings.

If LPG is not used for giving engine refuelling, method 300 that can proceed to 306 from 304 comprising activation DI It pumps and with high pressure mode operation DI injectors (for example, above DI fuel injectors 252 described in fig. 2).Therefore, method 300 include that will differ from the fuel (such as gasoline) of LPG to be supplied to DI rails (for example, the above DI described in fig. 2 at 306 One or more of fuel rail 250) and PFI rails (for example, above PFI fuel rails 260 described in fig. 2).To DI rails When supplying fuel (such as gasoline), via DI to pump fuel can be carried out by activating DI pumps and with pressurised mode operation DI pumps Pressurization.As above as described in Figure 2, can be pumped by the opening inlet valve during the intake stroke that DI is pumped and in DI Inlet valve is closed during compression stroke to activate DI to pump and pumped with pressurised mode operation DI.Therefore, method 300 includes at 306 Adjust inlet valve so that DI is pumped to the fuel addition pressure for being supplied to DI rails by elevator pump.

In addition, with high pressure mode operation DI injectors may include by the set point of DI rail pressure power (for example, it is desirable to DI rails Pressure) it is adjusted to higher first pressure.Therefore, controller can adjust elevator pump and/or DI pump inlet valve operation with Just DI rails are maintained at higher first pressure.By this method, when with non-LPG fuel to cylinder refuelling, can with than with Higher cylinder pressure injects fuel directly into engine cylinder when LPG is to cylinder refuelling.Method 300 is then back to.

304 are returned to, if providing power using LPG for engine, method 300 proceeds to 308 comprising deactivate DI It pumps and DI injectors is operated with low-voltage.Such as in greater detail above with reference to Fig. 2, deactivate DI pump include operation DI pump so that It is obtained not to the LPG addition pressure for being supplied to DI rails.For example, it may include the inlet valve supply electricity not pumped to DI to deactivate DI pumps Power so that fuel can flow freely through inlet valve during the intake stroke and compression stroke that DI is pumped.It is operated with low-voltage DI injectors may include that the set point of DI rail pressure power is adjusted to lower second pressure.It therefore, can be with when spraying LPG Desired pressure lower pressure when desired fuel rail pressure is adjusted to than spraying fuel (such as gasoline) different from LPG Power.Lower second pressure can be set based on the temperature of DI rails.Specifically, lower second pressure can be in DI rails LPG for current DI rails temperature will as liquid existing pressure.For example, lower second pressure can be set below The pressure of the liquid-gas transformation curve (its example is shown in FIG. 5) of LPG so that the LPG in DI rails is maintained at liquid.

In addition, including carrying out feedback control to the pressure of DI rails to reach than spraying difference with low-voltage operation injector Desired pressure lower pressure when the fuel of LPG and/or when DI pumps are in active state.Specifically, controller can be with Feedback control is carried out to the operation of elevator pump to reach the combustion being in active state than DI pumps and to the supply of DI rails different from LPG Desired pressure lower pressure when material.For example, when supplying LPG to DI rails, controller can reduce setting for DI rail pressure power Fixed point.

As explained in fig. 2 above, the set point of the DI rail pressure power when supplying LPG can be no more than elevator pump most Big pressure capability.Therefore, set point can be set below to the maximum pressure of elevator pump and/or the outlet pressure less than elevator pump Power.

In this way, it is possible to operate DI injectors with low-voltage to spray the outlet pressure base of its pressure and elevator pump This similar or lower LPG.It can be controlled through DI injectors based on the in-cylinder pressure of the pressure of DI rails and engine cylinder Injection timing.Specifically, DI injectors can wait LPG to be sprayed, until in-cylinder pressure is less than DI rail pressure power.Therefore, when When in-cylinder pressure is less than the outlet pressure of elevator pump, LPG can be directly injected in engine cylinder by controller, because can be with Feedback control is carried out to make it below or up to the outlet pressure of elevator pump to DI rail pressure power.

After setting desired fuel rail pressure to lower second pressure, method 300 can be proceeded to from 308 310 comprising promotion pump power is adjusted based on DI fuel rail pressures.Therefore, controller can be for example supplied to The duty ratio of the electric power of pump motor is promoted to adjust the amount of power provided to elevator pump, so that DI rail pressure power is maintained at lower Second pressure.As it is above explain in fig. 2, controller can by from DI rail pressure sensors (for example, it is above in fig. 2 The pressure sensor 248 of description) output that receives estimates DI rail pressure power.Then, controller can be based on the DI rail pressures of estimation Difference between power and lower second pressure promotes pump power so that DI rail pressures power is pressed closer to lower second to adjust Power.It can it is expected when spraying LPG to adjust according to engine operating condition (cylinder pressure, cylinder temperature, fuel temperature etc.) DI rail pressures power (for example, lower second pressure).

Then method 300 proceeds to 312 from 310 comprising determine whether it is expected intake port injection.In higher environment temperature (wherein LPG vaporizations are more likely) may expect intake port injection under degree and/or higher fuel cell temperature.At other In example, it can be desirable to intake port injection at a temperature of higher DI rails.For example, working as environment temperature, fuel cell temperature and DI rails When one or more of temperature increases to corresponding first threshold or more, it may be desirable that intake port injection.Threshold value can be set It is set to or becomes close to the liquid of LPG to gas phase, depend on pressure and can be by making pressure and LPG liquid-gas phase transition temperatures Relevant known relation (for example, look-up table) determines.Exemplary liquid-gas transformation curve is shown in Fig. 5.

Therefore, when the liquid LPG in DI rails is vaporized or close vaporization, it may be desirable that intake port injection, and therefore phase Hope cooling DI rails.By this method, when the fluid in DI rails is close to vaporization or when vaporizing, make port fuel spray and/or Center fuel injection is sprayed prior to direct fuel.For example, method 300 may include before starting directly injection LPG, pass through Steam jet ejector sprays the essentially all of steam in DI rails all steam is discharged.Therefore, if controller is based on The temperature and pressure of DI rails determines that there are steam in DI rails, then before starting directly injection liquid LPG, controller can be opened Steam jet ejector is to make gaseous state LPG be sprayed from DI rails.Therefore, fuel system can with intake port injection LPG to prevent and/or Reduce the LPG vaporizations in DI rails.It can be by the way that by the DI rails temperature measured, (the DI temperature obtained from DI rail temperature sensors measures Value) vaporization of the LPG in detection DI rails is compared to the liquid-gas phase transition temperature of the LPG under the DI rail pressure power of measurement.It is additional Ground or alternatively, when the pressure of PFI rails is sufficiently smaller than DI rails, it may be desirable that intake port injection so that LPG will be from DI rails It is discharged and is vaporized when being supplied to PFI rails.Therefore, method 300 may include that there are when steam or in DI rails in DI rails Without directly spraying (in the threshold value of the liquid-gas phase curve of LPG) when LPG approaches vaporization.

In some instances, it is expected intake port injection even if in PFI rails there are when liquid LPG.Controller can To be based on respectively from PFI temperature sensor and pressure sensor (for example, the above temperature sensor 259 described in fig. 2 and pressure Force snesor 258) obtain PFI rail temperature and pressures estimated value come estimate at PFI rails whether there is liquid LPG.Specifically, Controller can be based on the known relation between PFI rail pressures power and pressure and LPG liquid-gas phase transition temperatures (for example, LPG is made to press Power and the relevant inquiry table of LPG liquid-gas phase transition temperatures) determine the liquid-gas phase transition temperature of the LPG in PFI rails.

In addition, because can be sprayed by intake port injection rather than directly to reduce injector noise and pumping work(, institute It can be better than directly spraying with port fuel injection.

However, in other examples, there are when liquid LPG at PFI rails, it may be undesirable to intake port injection.Therefore, exist In such example, LPG is sprayed by passage injector when LPG that controller can be only in PFI rails is in gaseous form. For example, controller can whether there is liquid LPG based on the temperature and pressure of PFI rails to determine at PFI rails.

If undesirable intake port injection, method 300 from 312 proceed to 314 comprising without intake port injection, But LPG is supplied to PFI rails to keep desired steam jeting pressure, as the following described in more detail referring to Figure 4.It can be with base Desired steam jeting pressure is arranged in the liquid-gas pressure phase transition of LPG at a temperature of PFI rails temperature and current PFI rails.For example, Steam jeting pressure can be set smaller than to the liquid-gas pressure phase transition of the LPG at a temperature of front rail (for example, when front rail temperature Lower LPG existing pressure in liquid form).Therefore, controller can be estimated based on the measured value obtained from temperature sensor The temperature of PFI rails, and then desired PFI rail pressures power can be set below to the liquid-gas for the PFI rail temperature measured Pressure phase transition, so that the LPG in PFI rails is remained steam and prevents/reduce the condensation in PFI rails.Controller may include It is stored in the known relation (for example, look-up table) of the temperature and pressure of LPG and liquid-gas phase transformation in non-transient memorizer.In other words, Controller may include phase transformation table or curve graph, for given temperature or pressure provide respectively LPG liquid phase and gas phase it Between the corresponding pressure that changes or temperature.However, in other examples, desired steam jeting pressure can be set to liquid-gas Pressure phase transition is higher than liquid-gas pressure phase transition.

Method 300 can include additionally if the controller determine that the condensation of LPG is occurring, then making LPG at 314 Stopping flows to PFI rails.For example, when the threshold value of the reduction of PFI rail temperature and/or pressure rise to the set point of LPG is interior or reaches solidifying When node, controller can supply LPG with steam off injector and stopping from DI rails to LPI rails.Method 300 then from 314 after Continue 320 comprising determine whether it is expected directly to spray LPG.

Alternatively, it is expected intake port injection if determined at 312, method 300 can be by being first carried out 316 Hes 318 advance to 320.Therefore, if it is desired to intake port injection, then method 300 can proceed to 316 from 312.At 316, base Desired steam jeting pressure is determined in PFI rail pressures power and/or temperature.It, can will be desired as explained at 314 above Steam jeting pressure is set below the liquid-gas pressure phase transition of LPG at a temperature of current PFI rails.318 are proceeded to from 316, then may be used With the amount by adjusting the LPG for being supplied to PFI rails from DI rails, feedback control is carried out to reach desired steam to PFI rail pressure power Spray pressure.For example, controller can adjust the amount for the LPG for going out and being supplied to PFI rails from the DI sections of track by steam jet ejector, with Just PFI rail pressure power is maintained at desired steam jeting pressure to reduce and/or prevent the condensation in PFI rails.Therefore, controller It can increase in response to the reduction (this will reduce desired steam jeting pressure) of PFI rail temperature and/or measured PFI rail pressure power It is added to desired steam jeting pressure or more, steam off injector and the amount for reducing the LPG for being supplied to PFI rails.

Proceed to 320 from 318 or 314, when the LPG in DI rails is liquid and/or when in PFI rails there are when liquid LPG, It may expect directly to spray.Therefore, (its at a temperature of lower environment temperature, lower fuel cell temperature and lower DI rails Middle LPG is more likely to exist in liquid form), it may be desirable to directly spray.For example, working as environment temperature, fuel cell temperature and DI rails When one or more of temperature is reduced to corresponding second threshold or less, it may be desirable that directly spray.In some instances, may be used Second threshold is set above the above first threshold discussed at 312 so that between first threshold and second threshold In the presence of the temperature range of desired intake port injection and directly both injections.However, in other examples, second threshold can wait In or less than first threshold, intake port injection or one kind directly in injection may expect each time.

If undesirable directly injection, method 300 from 320 proceed to 322 comprising do not spray LPG directly, continue to PFI rails supply LPG, and by passage injector by one or more air inlets of LPG intake port injections to engine cylinder In pipeline.Method 300 is then back to.

However, if it is expected directly to spray at 320, method 300 can continue to 324 comprising determine desired Intake port injection amount and direct emitted dose.For example, controller can be determined passes through passage injector during cycle of engine Total volume of fuel or quality with the injection of both direct injectors is to realize desired air/fuel ratio, operator demand's torque Deng.Then, controller can divide the ratio of total volume of fuel or quality between direct injector and passage injector.? At 326, controller can start directly spray by the low fuel score (fraction) for the total volume of fuel or quality to be sprayed It penetrates.Therefore, controller can spray total volume of fuel of greater proportion by passage injector.In other words, direct when it is expected When injection, controller can by spray first less than under closed-loop control it is generally desirable to amount predetermined a small amount of fuel it is straight to start Connect injection.

Then, controller can determine that the LPG being directly injected in engine cylinder is liquid or gaseous state 328.Such as The LPG that fruit is directly sprayed is steam, then method 300 from 328 proceeds to 330 comprising reduces and/or stop the direct spray of LPG It penetrates and correspondingly increases intake port injection.Therefore, it is being sprayed if the LPG in DI rails is gaseous and direct injector LPG steam, then controller can be switched to only intake port injection LPG without directly spraying LPG.What controller can reduce with it Direct emitted dose proportionally increases intake port injection to keep total volume of fuel or quality.Method 300 is then back to.

It should be understood that in some instances, total volume of fuel or quality can depend on intake port injection with directly The ratio of injection.Therefore, controller can adjust total according to the opposite fuel score of direct injector and passage injector Volume of fuel or quality.

However, if determining that the LPG sprayed by direct injector is liquid at 328, method 300 from 328 proceeds to 332 comprising direct fuel injection score is increased to desired horizontal and correspondingly reduces intake port injection.For example, control Device may include look-up table or other known relations, and air inlet is determined for being directed to PFDI operations under the engine operating condition of variation The desired ratio that road is sprayed and directly sprayed.Therefore, when it is expected directly to spray LPG, if it is not known that the LPG directly sprayed is Liquid or gaseous state, then controller can be started by directly spraying a small amount of fuel.Once phase (the liquid of the LPG directly sprayed Body or gas) it is known that then controller can correspondingly adjust power operation.For example, if LPG is gaseous, control Device processed can reduce direct emitted dose；And if opposite LPG is liquid, controller can increase direct emitted dose.

It, can be substantially low in in-cylinder pressure (less than with high pressure mode injection and injection in the case where directly spraying LPG Different from LPG fuel when usual pressure) when spray LPG.For example, when piston is (for example, the above piston described in Fig. 1 138) when at or close to lower dead center (BDC), LPG can be sprayed by direct injector.However, in other examples, it can To adjust the timing that LPG directly sprays based on in-cylinder pressure.For example, when in-cylinder pressure be decreased below DI rail pressures power and/or When less than threshold value, LPG can be sprayed.For example, can be during intake stroke of the piston, or close to cylinder in piston intake punching LPG is sprayed when minimum in-cylinder pressure during journey.For example, during compression stroke, can be started to open up in inlet valve, or LPG is sprayed after inlet valve opening and before in-cylinder pressure starts to increase.Therefore, it does not spray during compression stroke LPG。

In another embodiment, instead of intake port injection or in addition to intake port injection, method 300 may include in using Entreat fuel injection (CFI).Therefore, instead of or in addition to the LPG from DI rails is supplied to PFI for example at 314,318 and 322 Except rail, this method may include that the LPG from DI rails is supplied to CFI injectors.In addition, instead of or in addition to for example exist 322, except LPG being ejected into air inlet port by PFI injector at 300 and 332, this method may include passing through CFI LPG is ejected into public inlet manifold by injector.Also, at 312, this method, which includes alternatively, or in addition determination, is No expectation CFI injection, this may with 312 at the same or similar mode of mode that has been described complete.

Method 300 is then back to.

With continued reference to Fig. 4, it illustrates the exemplary methods of DI rails and PFI rails for LPG to be supplied to fuel system 400.Method 400 starts at 402 comprising will based on the difference between desired DI rail pressures power and the DI rail pressure power of estimation LPG is pumped into DI rails from fuel tank.As explained above with reference to Fig. 3, can based on the output from DI rail pressure sensors come Estimate DI rail pressure power, and desired DI rail pressures power can be set to lower second pressure, in injection different from the combustion of LPG The lower second pressure is less than desired DI rail pressures when material and in the case where DI pumps are activated and are in pattern of pressure The pressure that power will be arranged to.Then method 400 from 402 proceeds to 404 comprising based on desired steam jeting pressure with estimate Difference between the PFI rail pressure power of meter adjusts the amount for the LPG for being supplied to PFI rails, such as it is above in figure 3 in greater detail. Therefore, controller can adjust the amount for the LPG that DI rails are supplied to PFI rails by adjusting steam jet ejector, and can distinguish The amount for the LPG for being supplied to PFI rails is increased or decreased by opening or closing steam jet ejector, is held so that PFI rail pressures are tried hard to keep In desired steam jeting pressure.

Then method 400 can advance to 406 from 404 comprising coordinate the supply of elevator pump operation and LPG to PFI rails. For example, at 407, when supplying more LPG to PFI rails from DI rails, controller can try to be the first increase promotion pump power to mend Estimated the expected of the DI rail pressure power caused by escapeing to the increase of LPG of PFI rails from DI rails is repaid to decline.In another example In, controller can postpone the increase of the LPG supplies to PFI rails to take into account the elevator pump acceleration time.Therefore, it controls Device can coordinate the operation of elevator pump and steam jet ejector and plan the expectation of their electrical power to change, so as to by DI rails and PFI rails are maintained at its corresponding desired pressure.

Method 400 can proceed to 408 from 406 comprising the LPG from DI rails is ejected into cooling chamber (above in Fig. 2 Described in cooling chamber 256) in and LPG is depressurized.Can by open steam jet ejector come realize LPG is ejected into it is cold But in room.For example, controller can adjust the pulse width for the command signal for being sent to steam jet ejector.Because controller will PFI rails maintain pressure more lower than DI rail (by keeping steam jet ejector to close other than when spraying LPG), so The pressure of LPG reduces later in being ejected into cooling chamber.Therefore, when LPG to be ejected into from DI rails in cooling chamber, the temperature of LPG Degree reduces, and in some instances, if LPG has not been steam, can be vaporized.

Then method 400 proceeds to 410 from 408 comprising cool down DI rails using the LPG for including in cooling chamber.Therefore, Since LPG is depressurized and cooled down when it is injected into cooling chamber, cooling chamber may be at temperature more lower than DI rail.It is logical It crosses and is positioned to thermally contact with DI rails (as being explained in more detail above with reference to Fig. 2) by cooling chamber, the colder LPG in cooling chamber can be with Heat is absorbed from DI rails, to reduce the temperature of DI rails.LPG in heating cooling chamber reduces the condensation of gaseous state LPG, to really It protects to PFI rails and supplies LPG steam.In addition, cooling down the vaporization that DI rails reduce the LPG in DI rails using the LPG in cooling chamber And increase the amount for the liquid LPG that can be used for directly spraying.In this way, it is possible in the engine operating temperature of wider range With keep more stable LPG to spray in environment temperature.That is, by the way that hotter, elevated pressures the LPG in DI rails is exposed Colder in cooling chamber, lower pressure LPG, can realize liquid LPG injection at higher ambient temperatures, and with by from LPG is independently directed to each fuel rail and is compared to realize that steam LPG sprays by elevator pump, can be under lower environment temperature Realize steam LPG injections.

Then method 400 proceeds to 412 from 410 comprising LPG is made to flow to PFI rails from cooling chamber.Then, at 414, The LPG in PFI rails can be ejected into the air inlet port of engine cylinder as needed.

However, in another embodiment, method 400 can include alternatively that LPG is made to flow to common fuel from cooling chamber Injection (CFI) injector so as to inject fuel into public inlet manifold rather than air inlet port.Therefore, method 400 can be with Do not include 412 and 414, and LPG can be made to flow to CFI injectors from DI rails, rather than LPG is made to flow to PFI rails from DI rails, and And may include being injected fuel into public inlet manifold by CFI injectors, rather than will be fired by passage injector Material is ejected into different air inlet ports.

As method 400 416 at indicated, once LPG pump is sent to DI rails by elevator pump, controller is just not LPG can be made to flow back into the upstream of DI rails.That is, The fuel stream will not flow back into fuel tank from DI rails.Therefore, fuel can only lead to It crosses and is directly injected in engine cylinder or is ejected into PFI rails to leave DI rails.By this method, controller makes LPG from DI rail streams To PFI rails, without making LPG flow to any part for the fuel system that DI rails upstream includes.Therefore, from DI rails 250 to PFI rails In 260 way, LPG at most flow only through cooling chamber and couple PFI rails and DI rails one or more PFI supply lines (for example, The PFI supply lines 246 that describe in fig. 2 above and 266).Method 400 is then back to.

Fig. 5 is gone to, it illustrates the figure 500 of the example liquid-gas transformation curve 502 of LPG, which can be used for Determine the phase (liquid or gas) of the LPG in fuel system component (for example, above DI rails 250 described in fig. 2).Figure 500 along horizontal axis show by degree Celsius as unit of exemplary temperature, and shown with bar (Bar) along vertical axis For the example pressure of unit.Figure 500 can be stored in the non-of controller (for example, above controller 222 described in fig. 2) In transient storage, and can be used for based on the temperature of fuel system component and/or pressure come determine fuel system (for example, The fuel system 200 described in fig. 2 above) in LPG be gaseous state or liquid.When the measuring temperature and pressure of LPG are drawn To the top of transformation curve 502 point when, LPG is liquid；And when the measuring temperature of LPG and pressure are plotted to transformation curve When the point of 502 lower sections, LPG is gaseous.Therefore, in the example of hgure 5, for given temperature, it is more than if measuring pressure (being higher than) liquid-gas transformation curve 502, then LPG can be in liquid form；And when pressure is less than (being less than) liquid-gas transformation curve When 502, LPG can be in gaseous form.Similarly, for given pressure, if measuring temperature is more than liquid-gas transformation curve 502 (on the right side of them), then LPG can be gaseous；But if measuring temperature is less than liquid-gas transformation curve 502 (to the left), Then LPG can be liquid.

Therefore, controller can be by the way that the estimation temperature and pressure of LPG to be compared to liquid-gas transformation curve 502 Determine the LPG in special fuel system unit (for example, the above DI fuel rails 250 described in fig. 2 and PFI fuel rails 260) It is gaseous form or liquid form.

In a kind of expression, a kind of method includes：Liquefied petroleum gas (LPG) from fuel rail is supplied to fuel is straight Connect the direct injection injector in the cylinder for being ejected into engine；And it is not direct injection spray so that LPG is flow to from the fuel rail The charge-air fuel injector of emitter is without making the LPG flow back into fuel tank, wherein the charge-air fuel injector is from the vapour Position outside cylinder injects fuel into the air intake duct for supplying the cylinder.In first example of the method, it is described into Gas fuel injector includes the port fuel injector in the air inlet port for inject fuel into the cylinder, and is wherein made The LPG from the fuel rail flow to the charge-air fuel injector include first make the LPG from the fuel rail flow into Gas-duct jetting fuel rail, and the LPG is then made to flow to the charge-air fuel injector from the intake port injection fuel rail. Second example of the method optionally includes first example and further comprises：It will by the first fuel supply lines Liquefied petroleum gas (LPG) is pumped into the fuel rail from the fuel tank, wherein the LPG is pumped into institute from the fuel tank It includes the LPG being pumped into the fuel rail from the fuel tank merely with elevator pump, and do not utilize higher to state fuel rail Compression pump or direct jet pump further pressurize to the LPG.The third example of the method optionally includes described first and shows Example and one or more of second example and further comprise：Wherein described first fuel supply lines are in first end On be connected to the fuel tank and be connected to the arrival end of the fuel rail in opposite second end, and the wherein second combustion The fuel rail is connected to the charge-air fuel injector by material supply line, wherein second fuel supply lines are connected to The outlet end of first fuel rail, the outlet end are different from the arrival end.4th example of the method is optionally wrapped Described first is included to one or more of third example and is further comprised：At the charge-air fuel injector LPG condenses, and stops LPG from the fuel rail to the flowing of the charge-air fuel injector.5th example of the method is optional Ground includes one or more of described first to fourth example and further comprises：The wherein described charge-air fuel injector packet Include the central fuel injector in the inlet manifold for injecting fuel into the engine.6th example of the method is optionally Including one or more of the described first to the 5th example and further comprise：LPG is wherein set to be flowed to from the fuel rail The charge-air fuel injector includes being ejected into LPG in cooling chamber from the fuel rail, wherein the pressure of the cooling chamber is low In the pressure of first fuel rail.7th example of the method optionally includes in first example to six example One or more and further comprise include：Wherein make LPG from the fuel rail flow to the charge-air fuel injector into One step, which is used, is included in the cooling indoor vaporization LPG coolings fuel rail.8th example of the method optionally includes First example is to one or more of seven example and further comprises：Feedback control is carried out to protect to elevator pump The pressure for holding the fuel rail is less than the desired pressure in fuel of the direct injection different from LPG.The 9th of the method Example optionally includes one or more of the described first to the 8th example and further comprises：It will not make institute first It states LPG and flows through and LPG is pumped directly into the charge-air fuel injector from the fuel tank in the case of the fuel rail.

In another expression, a kind of method includes：By the first fuel supply lines by liquefied petroleum gas (LPG) from fuel Case is pumped into the first fuel rail；And LPG is supplied to the second combustion from first fuel rail by the second fuel supply lines Rail is expected, without making the LPG flow back into the fuel tank or first fuel supply lines.In first example of the method In, first fuel rail includes that directly injection (DI) fuel rail and second fuel rail includes port fuel injection (PFI) rail.Second example of the method optionally includes first example and further comprises：Wherein by the LPG It includes that the LPG is pumped into institute from the fuel tank merely with elevator pump to be pumped into first fuel rail from the fuel tank The first fuel rail is stated, and elevated pressures pump or directly jet pump is not utilized further to pressurize the LPG.The of the method Three examples optionally include one or more of first example and second example and further comprise：Wherein institute The first fuel supply lines are stated to be connected to the fuel tank in first end and be connected to described in opposite second end The arrival end of one fuel rail, and wherein described second fuel supply lines are connected to first fuel rail in first end Outlet end, the outlet end is different from the arrival end, and second fuel rail is connected in opposite second end Arrival end.4th example of the method optionally includes described first to one or more of third example and further Including：LPG is directly injected to from first fuel rail in engine cylinder by direct injector.The 5th of the method Example optionally includes one or more of described first to fourth example and further comprises：It is sprayed by port fuel Emitter is by LPG from the second fuel rail intake port injection to the air inlet port of engine cylinder.The 6th of the method shows Example optionally includes one or more of the described first to the 5th example and further comprises：Wherein by LPG from described One fuel rail be supplied to second fuel rail include the LPG from first fuel rail is ejected into cooling chamber, wherein The pressure of the cooling chamber is less than the pressure of first fuel rail.7th example of the method optionally includes described first Example is to one or more of six example and further comprises：Wherein LPG is supplied to from first fuel rail Second fuel rail includes cooling down first fuel rail with the vaporization LPG for including in second fuel supply lines, Described in vaporization LPG pressure be less than first fuel rail pressure.8th example of the method optionally includes described First example is to one or more of seven example and further comprises：It wherein will by the first fuel supply lines LPG is pumped into first fuel rail from the fuel tank, carries out feedback control to elevator pump to keep first combustion Expect that the pressure of rail is less than the desired pressure in fuel of the directly injection different from LPG.9th example of the method is optional Ground includes one or more of the described first to the 8th example and further comprises：The LPG will not be made to flow first It crosses and LPG is pumped directly into second fuel rail from the fuel tank in the case of first fuel rail.

In another expression, a kind of method for engine may include：LPG is pumped into direct injection from fuel tank (DI) fuel rail；Liquid LPG is directly injected to institute by the one or more directly injector by being connected to the DI fuel rails In at least one cylinder for stating engine；And by vaporize LPG and be sprayed onto from the DI fuel rails be not direct injector air inlet Injector.In first example of the method, the method may further include：Direct jet pump is deactivated, wherein deactivating The direct jet pump includes that the direct jet pump is kept during the intake stroke and compression stroke of the direct jet pump Inlet valve open so that the direct jet pump will not to be pumped by elevator pump the DI fuel rails LPG add pressure Power, and it includes only being added to the LPG with the elevator pump that LPG is wherein pumped into the DI fuel rails from the fuel tank Pressure.Second example of the method optionally include first example and further：Wherein liquid LPG is directly injected to At least one cylinder of the engine includes, when cylinder pressure is less than the outlet pressure of the elevator pump, by LPG low pressure It is directly injected in the engine cylinder.The third example of the method optionally includes first example and described second One or more of example and further comprise：When the temperature of PFI fuel rails is more than second threshold, pass through the air inlet Injector by LPG from PFI fuel rails intake port injection to the air inlet port of the cylinder of engine in, wherein the air inlet injector Including passage injector, and wherein liquid LPG is directly sprayed when the temperature of the DI fuel rails is less than first threshold At least one cylinder to the engine includes that low pressure directly sprays LPG.4th example of the method optionally includes Described first to one or more of third example and further comprises：The wherein described first threshold is more than second threshold Value so that between the first threshold and the second threshold, the method includes both directly spraying with intake port injection. 5th example of the method optionally includes one or more of described first to fourth example and further comprises：? When directly spraying with intake port injection, start the direct injection with the LPG of predetermined amount, and then when spraying liquid LPG Increase the direct injection and reduces the direct injection when spraying gaseous state LPG.6th example of the method is optionally Including one or more of the described first to the 5th example and further comprise：It is sprayed onto by adjusting from the DI fuel rails The amount of the LPG of the PFI fuel rails, to PFI fuel rails progress feedback control to reach pressure more lower than the DI fuel rails, Feedback control wherein is carried out to make it below the liquid-gas phase transformation of the LPG in the PFI fuel rails to the PFI fuel rail pressures Pressure.7th example of the method optionally include first example to one or more of six example and into One step includes：Feedback control wherein is carried out to make it below the LPG's in the PFI fuel rails to the PFI fuel rail pressures Liquid-gas pressure phase transition includes：The liquid-gas phase-change pressure of the LPG in the PFI fuel rails is determined based on current PFI fuel rails temperature Power；Desired PFI fuel rail pressures are set below identified liquid-gas pressure phase transition；And adjustment by LPG from the DI Fuel rail is supplied to the injector of the PFI fuel rails, so that the PFI fuel rail pressures are maintained at desired PFI fuel Rail pressure power.

In another expression, a kind of fuel system includes：Elevator pump；Direct fuel injection rail is supplied by the first fuel Pipeline is answered to be connected to the elevator pump；Intake port injection fuel rail in the downstream of the direct fuel injection rail and passes through Second fuel supply lines and the direct fuel injection rail coupled in series, wherein the intake port injection fuel rail and described the Two fuel supply lines are in pressure more lower than the direct fuel injection rail；Injector is used to come from described direct The fuel of injection fuel rail is supplied to the intake port injection fuel rail；And controller, with the elevator pump and the spray Emitter is electrically connected, and the controller includes the computer-readable instruction being stored in non-transient memorizer, and described instruction is used for：With The direct jet mode of low pressure carries out feedback control to the elevator pump；And feedback control is carried out to the injector to keep The pressure of the intake port injection fuel rail is less than the pressure of the direct fuel injection rail and is less than LPG liquid-gas pressure phase transitions, Temperature of the LPG liquid-gas pressure phase transition based on the intake port injection fuel rail.The fuel system can also include cooling Room, the cooling chamber are located in second fuel supply lines and are thermally contacted with the direct fuel injection rail, with In cooling down the direct fuel injection rail by the lower pressure fuel in second fuel supply lines.

In another expression, a kind of method for engine includes：Liquefied petroleum gas (LPG) is straight from the first fuel rail It connects and is ejected into engine cylinder；LPG is supplied to the second fuel rail from first fuel rail；And by LPG from described In two fuel rail intake port injections to the air inlet port of the cylinder.

In another expression, a kind of method for engine includes：When DI fuel rails temperature be less than temperature threshold with And the pressure of cylinder be less than pressure threshold in it is one or more in the case of, pass through one or more fuel injections of DI fuel rails LPG not yet by DI pump pressurizations is directly injected in engine cylinder by device；And it is sprayed by one or more fuel of PFI rails Emitter will be in the air inlet port of LPG intake port injections to the cylinder.

In another expression, a kind of method for engine includes：LPG is pumped into DI fuel rails from fuel tank；Make Vaporization LPG gases in the DI fuel rails are flowed out from the DI fuel rails；The vaporization LPG gases are depressurized；Pass through The LPG gases of decompression are made to flow through the DI fuel rails to cool down the LPG in the DI fuel rails；And by the LPG of the decompression Gas is supplied to PFI fuel rails.

In another expression, a kind of method for engine includes：Deactivate DI petrolifts；By elevator pump by LPG from Fuel tank is pumped into DI fuel rails and PFI fuel rails；And cylinder pressure and fuel temperature are based on from the DI fuel rails or institute State PFI fuel rails or both injection LPG.

In another expression, a kind of method for engine includes：When the temperature of the DI fuel rails is more than threshold value, It deactivates and is located at one or more of DI fuel rails direct fuel injector, and only sprayed by one or more port fuels LPG is ejected into the air inlet port of engine cylinder by emitter；And when the temperature of the DI fuel rails increases to the threshold value When above, reactivate the direct fuel injector, it is described reactivate including：Directly spray the fuel of predetermined amount；It determines The fuel directly sprayed is liquid or gaseous state；The fuel of injection in response to the determination predetermined amount is liquid, will directly be sprayed The fuel quantity penetrated increases to desired amount from the predetermined amount；And in response to the fuel of injection of the determination predetermined amount it is gas State deactivates the direct injector.

By this method, LPG is directly sprayed by low pressure come realize reduce fuel system cost and complexity technique effect, Because can from fuel system removal/omission elevated pressures direct jet pump.It is retained in fuel system in direct jet pump In but become in the example of inactive state, the use of pump can be enhanced by reducing amount into the fuel vapour of pump intake Service life.Can by fuel system omit fuel return line and be originated from directly spray rail decompression (and because This cooling) steam cooling directly injection rail reduce fuel vapour.It omits fuel return line and further reduces fuel system The cost and complexity of system.

Furthermore, it is possible to by realizing that reduction air-fuel ratio error, increase are sent out with the LPG steam of decompression cooling directly injection rail Motivation performance and the technique effect for increasing LPG temperature operating ranges.The further vapour of the LPG in directly injection rail can be reduced Change, thus reduces air-fuel ratio error, reduces pinking and increase engine performance and stability.Accordingly, by using hotter Direct fuel injection rail heat the LPG steam of decompression, the LPG condensations in port fuel injection rail can be reduced, thus Reduce air-fuel ratio error and increases engine performance and stability.It therefore, can be in the environment temperature and engine of wider range Firm LPG engine refuellings are realized under operation temperature.

It should be appreciated that configuration disclosed herein and routine program are exemplary in itself, and these are specific real Apply example be not considered as it is restrictive because it is many variation be possible.For example, above-mentioned technology can be applied to V-6, I-4, I-6, V-12, opposed 4 cylinder and other engine types.The theme of the disclosure include various systems disclosed herein and configuration with And other features, all novel and non-obvious combination of function and/or attribute and sub-portfolio.

It is considered as novel and non-obvious certain combinations and sub-portfolio that following following claims, which particularly points out,.These power Sharp requirement can refer to "one" element or " first " " element or its equivalent.Claim is understood to include one in this way The merging of this or multiple class component, both two or more neither requiring nor excluding this class components.It can be by changing this power Profit require or by new claim is proposed in the application or related application come be claimed disclosed feature, function, Other of element and/or attribute combine and sub-portfolio.Such claim, no matter in range compared with original claim more It is wide, narrower, equal or different, it is recognized as including in the theme of the disclosure.

Claims

1. a kind of method comprising：

Liquefied petroleum gas, that is, LPG from fuel rail is supplied to direct injection injector, the direct injection injector is direct by LPG It is ejected into the cylinder of engine；And

Make LPG flow to from the fuel rail be not direct injection injector charge-air fuel injector, without make the LPG return Fuel tank is flowed to, wherein LPG is ejected into the supply cylinder by the charge-air fuel injector from the position outside the cylinder Air intake duct in.

2. according to the method described in claim 1, the wherein described charge-air fuel injector includes injecting fuel into the cylinder Air inlet port in port fuel injector, and the LPG is wherein made to flow to the charge-air fuel from the fuel rail Injector includes so that the LPG is flowed to intake port injection fuel rail from the fuel rail first, and then make the LPG from institute It states intake port injection fuel rail and flows to the charge-air fuel injector.

3. according to the method described in claim 1, its further include by the first fuel supply lines by liquefied petroleum gas i.e. LPG from The fuel tank is pumped into the fuel rail, wherein it includes only sharp that the LPG is pumped into the fuel rail from the fuel tank The LPG is pumped into the fuel rail from the fuel tank with elevator pump, and elevated pressures is not utilized to pump or directly spray Pump further pressurizes to the LPG.

4. according to the method described in claim 3, wherein described first fuel supply lines are connected to the combustion in first end Hopper and the arrival end that the fuel rail is connected in opposite second end, and wherein the second fuel supply lines are by institute It states fuel rail and is connected to the charge-air fuel injector, wherein second fuel supply lines are connected to first fuel rail Outlet end, the outlet end of the fuel rail is different from the arrival end.

5. according to the method described in claim 1, it further comprises coagulating at the charge-air fuel injector in response to LPG Knot stops LPG from the fuel rail to the flowing of the charge-air fuel injector.

6. according to the method described in claim 1, the wherein described charge-air fuel injector includes that LPG is ejected into the engine Inlet manifold in central fuel injector.

7. according to the method described in claim 1, wherein making LPG flow to the charge-air fuel injector from the fuel rail to include LPG is ejected into from the fuel rail in cooling chamber, wherein the pressure of the cooling chamber keeps below the pressure of the fuel rail.

8. also being wrapped according to the method described in claim 7, LPG is wherein made to flow to the charge-air fuel injector from the fuel rail It includes and cools down the fuel rail with included in the indoor vaporization LPG of the cooling.

9. according to the method described in claim 1, it further comprises carrying out feedback control to elevator pump to keep the fuel Rail desired pressure lower pressure when being in than directly spraying the fuel different from LPG.

10. according to the method described in claim 1, it further comprises not making the LPG first flow through the fuel rail In the case of LPG is pumped directly into the charge-air fuel injector from the fuel tank.

11. according to the method described in claim 1, its further comprise when cylinder pressure be less than elevator pump outlet pressure when, Liquid LPG low pressure is directly injected in the cylinder of the engine by the direct injector.

12. according to the method for claim 11, further comprising the air inlet combustion by not being direct injection injector Material ejector is sprayed by LPG intake port injections to the air intake duct for supplying the cylinder, and in directly injection and air intake duct When penetrating, start the direct injection with the LPG of predetermined amount, and then increase when spraying liquid LPG the direct injection with And reduce the direct injection when spraying gaseous state LPG.

13. according to the method described in claim 1, it further comprises being supplied to the air inlet by the fuel rail by adjusting The amount of the LPG of fuel injector carries out feedback control to reach more higher than the charge-air fuel injector to the fuel rail Pressure, wherein carrying out feedback control to the pressure at the charge-air fuel injector to make it below the charge-air fuel injector Current Temperatures under LPG liquid-gas pressure phase transition.

14. a kind of fuel system comprising：

Elevator pump；

Direct fuel injection rail is connected to the elevator pump by the first fuel supply lines；

Intake port injection fuel rail, the downstream of the direct fuel injection rail and by the second fuel supply lines with it is described Direct fuel injection rail coupled in series, wherein the intake port injection fuel rail and second fuel supply lines are in than institute State the lower pressure of direct fuel injection rail；

Injector is connected between the direct fuel injection rail and the intake port injection fuel rail described to come from The fuel of direct fuel injection rail is supplied to the intake port injection fuel rail；And

Controller is electrically connected with the elevator pump and the injector, and the controller includes being stored in non-transient memorizer In computer-readable instruction, described instruction is used for：

Feedback control is carried out to the elevator pump with low pressure direct jet mode；And

Feedback control is carried out to the injector to keep the pressure of the intake port injection fuel rail to be less than the direct spray It penetrates the pressure of fuel rail and is less than LPG liquid-gas pressure phase transitions, the LPG liquid-gas pressure phase transition is fired based on the intake port injection Expect the temperature of rail.

15. fuel system according to claim 14 further comprises that cooling chamber, the cooling chamber are located in described It is thermally contacted in two fuel supply lines and with the direct fuel injection rail, will pass through in second fuel supply lines Lower pressure fuel cool down the direct fuel injection rail.